**1. Introduction**

With the continuous change in globalization, urbanization, and increase in population, people migrate from one region to another for a better quality of life. This in turn leads to increase in population in such regions. Therefore, there is need to make provisions for infrastructures that will support this increase. The construction industry provides the necessary structure and infrastructure needed for a sustainable environment. However, this sector is faced with different environmental impacts throughout its production cycle. Concrete is one of the important materials in the construction Industry. The production of concrete is required to build the global landscape and accommodate the continuous urbanization as a result of

population growth. Recently, construction sector has been recorded to produce large environmental impact which is of continuous concern to the society [1–4]. Ordinary Portland Cement (OPC) is the major constituent of concrete production. Several environmental impacts such as intensive resource and energy consumption are associated with the production of cement [5–9]. This continuous increase in the environmental impacts of the cement industry at the global level is beckoning for attention because of the possible consequences that can succeed these impacts of great concern.

The OPC consists majorly of calcium silicate minerals (limestone, sand and clay) which are extracted and thereafter transferred to the manufacturing plant where they are crushed and finally pulverized into the required texture. This is preheated and eventually transferred into a large kiln of over 1400°C for further treatment to produce the clinker [2, 10]. The clinker is allowed to cool while the heat is trapped back to the preheater unit and gypsum is added to the cooled clinker to control the setting time of the OPC produced. Clinker production is the most energy consuming of all the production stages as enormous source of fuel and electricity is needed [11, 12]. As a result, cement industry is accountable for about 12-15% of industrial energy use [13–15]. Also, about 5-7% of global CO2 emission is produced during cement production [16]. About 2.6Gt of CO2 gas emission was recorded from production of cement in 2011, whereby the emission was from the combustion of fossil fuels and the thermal decomposition of limestone (calcination) [17, 18]. International Energy Agency's (IEA) Greenhouse Gas R&D Programme recorded that over 800 g of CO2 is emitted for every 1000 g of cement produced [19, 20]. Approximately 1 ton of concrete is needed annually by every individual, this makes cement an essential material which requires continuous production [5, 21, 22]. There is a need to quantify the environmental impact of the global production of cement production; the consequent effect on human health, resources and the environment as a whole; and production phases that cause the impacts so that proper recommendation and mitigation strategies can be presented. Studies have shown that the clinker production phase has the highest impact and CO2 is one of the most emitted gases [1, 8, 12, 23]. Recommendation on mitigation strategies varying from partial replacement of clinker, to use of alternative fuel etc. were given. Also, incorporation of best available techniques (BAT) to the production processes were part of the recommendations given [1, 24, 25].

Life cycle assessment (LCA) is a system-oriented tool used for the evaluation and assessment of a product's or process' environmental impacts by analyzing the entire stages of a production process beginning from resource extraction ("cradle") and continues through cement production, to cement applications like concrete structures, their use, and end-of-life (grave) [26]. This brings about the other name known as "cradle to grave". LCA gives a holistic view of the entire production process. According to International Standard Organization (ISO) 14040, the four stages of LCA are represented in **Figure 1** [28, 29].

• Goal and scope describe the assessment objectives alongside with the system of the product and/or process, functional unit, target audience, system boundaries, assumptions etc. It basically defines the jurisdiction of the assumption [30]. The functional unit that will be adopted in this study is 1kilogram of cement. All dataset, analysis and interpretation will take into account this functional unit. This study aims to analyze the environmental impact of 1 kg of cement using midpoint and endpoint LCIA approaches so as to rightly quantify the level of impact and make proper recommendation. The study will be conducted from cradle to gate i.e., from extraction to the production of cement. All data or information with respect to administration in *Life Cycle Assessment of Ordinary Portland Cement (OPC) Using both Problem… DOI: http://dx.doi.org/10.5772/intechopen.98398*

the plant, packaging processes and disposal will not be incorporated into the analysis.


Several studies have been carried out with respect to life cycle assessment of the cement industry to evaluate the impact of its production processes [2, 21, 34–36].

Often times, these studies are modeled after a country, or particular cement plant in a certain place. Rarely do we find LCA study modeled after the world. Also, more studies are more focused on using the midpoint approach only. This study will therefore carry out a life cycle assessment modeled after the rest of the world other than from China, India, Europe, US and Switzerland using both endpoint and midpoint approaches to analyze the environmental impact of OPC production. The remainder of this article is divided into method under section two, results under section three, discussion under section four and the last section concludes.
